1. Field
Apparatuses and methods consistent with exemplary embodiments relate to a receiving apparatus and a signal processing method thereof and, more particularly, to a receiving apparatus configured to receive a ground wave broadcasting signal, and a signal processing method thereof.
2. Description of Related Art
A digital terrestrial multimedia broadcasting (DTMB) standard, which is a standard for a Chinese HDTV, supports both an orthogonal frequency-division multiplexing (OFDM) scheme and a single carrier scheme. A pilot section of the DTMB system exists in a time domain, and the DTMP system may transmit data using the OFDM (frequency domain transmission) scheme and the single carrier (time domain transmission) scheme. Due to an obstacle, multipath fading may occur, and a synthesis signal formed by the multipath fading may change in strength in terms of time and space, affecting the communication quality.
FIG. 1A illustrates the case where a signal transmitted from an antenna on one side linearly reaches an antenna on the other side, and the case where the signal reaches the antenna by reflecting on a building. The reflection causes delay with respect to the reflected signal in comparison with a linear signal, thereby degrading communication quality.
FIGS. 1B and 1C illustrate a method for solving multipath fading according to a PN mode. A transmission standard of ground wave televisions for China is composed of a TDS-OFDM scheme and a single carrier scheme. The single carrier scheme is composed of three PN modes: PN 420, PN 595, and PN 945.
The PN 420 and PN 945 modes are such that different PNs, that is, different reference signals, are inserted per frame, as illustrated in the first drawing of FIG. 1B, thereby degrading accuracy of data recovery. To solve this problem, PN 420 and PN 495 modes remove the reference signal and change data to a cyclic structure using an overlap add (OLA). Also, data recovery is performed in the state that the reference signal is removed, using 3780 DFT iterative block decision feedback equalization (IBDFE).
FIG. 1C illustrates a PN 595 mode, and the PN 595 mode is such that the same PN, that is the same reference signal, is inserted per frame. Although FIG. 1C distinguishes PN1 from PN2, this is merely to mark the order of PN, and the PN1 and the PN2 actually have the same value. Because the PN1 and the PN2 are identical to each other, a frame may maintain a cyclic structure in case of multipath fading, and the PN 595 mode may recover data using 4375 DFT IBDFE which is obtained by adding 595 (Reference signal) and 3780 (data).
Accordingly, the PN 420 and PN 945 modes which only use data may cause degradation of performance compared with the PN 595 mode which additionally uses a reference signal, bringing about performance deviation between modes. Furthermore, there is a need for 3780 DFT with respect to the PN 420 and PN 945 modes and 4375 DFT with respect to the PN 595 mode, causing complexity in hardware and cost increase.